Although crystal facet engineering is extensively studied in energy and environmental technologies, the in-depth understanding of intrinsic mechanisms governing crystal facet heterojunctions in tuning band alignments is still limited. Here, novel Bi₅O₇NO₃ crystals exposing tailor {080} facets are synthesized via NH₄⁺-assisted self-confined construction. It has been confirmed that NH₄⁺ ions selectively adsorb on the {141} facets, inversely inducing the growth of desired {080} crystal facets, while the tailored {080} facets facilitate the generation of oxygen vacancies. The controllable concentration of oxygen vacancies, influenced by different exposed facets, can optimize the relative positions of Fermi levels and shift the photoelectron transfer route between the {141} and {080}-OV facets from type-II to S-scheme, thus triggering rapid charge transport channels and effectively suppressing electron-hole recombination. DFT calculation verifies that the energy barrier for the *COOH formation on Bi₅O₇NO₃-{080}-OV is the lowest, thereby promoting the generation of CO. The well-designed Bi₅O₇NO₃ crystals with the optimal {080}/{141} facet ratio exhibit a 3.8-fold enhancement in photocatalytic CO₂ reduction, compared to traditional Bi₅O₇NO₃ dominated by the {141} facets. This work offers new insights into the regulation of band alignments at heterointerfaces and the design of high-efficiency photocatalysts.

中文翻译：

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具有可调谐带对准的刻面异质结的自限结构，用于增强光催化 CO2 还原


尽管晶体刻面工程在能源和环境技术方面得到了广泛的研究，但对调谐带对齐中控制晶体刻面异质结的内在机制的深入理解仍然有限。在这里，通过 NH₄⁺ 辅助自限域结构合成了暴露裁缝{080}面的新型 Bi₅O₇NO₃ 晶体。已经证实，NH₄⁺ 离子选择性地吸附在{141}面上，反向诱导所需的 {080} 晶体刻面的生长，而定制的 {080} 刻面有助于氧空位的产生。受不同暴露面影响的氧空位浓度可控，可以优化费米能级的相对位置，并将 {141} 和 {080}-OV 面之间的光电子转移路线从 II 型转变为 S 型，从而触发快速电荷传输通道，有效抑制电子-空穴复合。DFT 计算验证了 Bi₅O₇NO₃-{080}-OV 上形成 *COOH 的能垒最低，从而促进了 CO 的产生。与以 {141} 刻面为主的传统 Bi₅O₇NO₃ 晶体相比，设计精良的 Bi₅O₇NO₃ 晶体具有最佳的 {080}/{141} 刻面比，光催化 CO₂ 还原能力提高了 3.8 倍。这项工作为异质界面处能带对准的调节和高效光催化剂的设计提供了新的见解。